GetAllStringsByCulture returns different result than GetStringByCulture with missing strings

Description

Steps to reproduce

1. Use a language file with this content:

<?xml version="1.0" encoding="utf-8"?>
<languages>
    <language name="français" id="fr">
        <test>
            <string1>French string 1</string1>
        </test>
    </language>
    <language name="English" id="en">
        <test>
            <string1>English string 1</string1>
            <string2>English string 2</string2>
        </test>
    </language>
</languages>

2. Set the localization element in Framework.config to have missing messages

<localization fallbackBehavior="MissingMessage, Echo" fallbackCulture="en">

3. Add the following code to a razor view (Example: /Views/Shared/Header.cshtml in alloy mvc templates)

@{
    var resourceItems = EPiServer.Framework.Localization.LocalizationService.Current.GetAllStringsByCulture("test", System.Globalization.CultureInfo.GetCultureInfo("fr"));
    foreach (var item in resourceItems)
    {
        @String.Format("GetAllStringsByCulture Results -> Key: {0} Value: {1}", item.Key, item.Value)
        <br />
        var getStringByCulture = EPiServer.Framework.Localization.LocalizationService.Current.GetStringByCulture(item.Key, System.Globalization.CultureInfo.GetCultureInfo("fr"));
        @String.Format("GetStringByCulture Results -> Key: {0} Value: {1}", item.Key, getStringByCulture);
        <br />
    }
}

Expected:
The output from GetAllStringByCulture produces the same result as GetStringByCulture.

Actual:
There's a difference on the string that has a translation in English but not French:

GetAllStringsByCulture Results -> Key: /test/string2 Value: [Missing text '/test/string2' for 'English']
GetStringByCulture Results -> Key: /test/string2 Value: [Missing text '/test/string2' for 'French']